prd-guided analgesia during fess for intraoperative blood loss

Conditions: Endoscopic Sinus Surgery

Summary: the aim of this randomized trial is to assess the utility of pupillary dilatation reflex (prd) for monitoring pain perception intraoperatively and its influence on intraoperative blood loss, quality of surgical field using boezaart bleeding scale (bbs) in patients undergoing functional sinus surgery (fess) under total intravenous anaesthesia using propofol or volatile anaesthesia using sevoflurane or desflurane

intraoperative blood loss during fess constitutes a major problem for a surgeon because it influences quality of surgical field. each incident of haemorrhage makes the operator stop the procedure in order to bring back the optimal visualization of the intranasal anatomy. in the end it prolongs the time of procedure. currently, intraoperative blood loss is estimated based on boezaart bleeding scale (bbs) (0 - no bleeding (cadaveric conditions), 1 - slight bleeding, no suctioning required, 2 - slight bleeding, occasional suctioning required, 3 - slight bleeding, frequent suctioning required; bleeding threatens surgical field a few seconds after suction is removed, 4 - moderate bleeding, frequent suctioning required, and bleeding threatens surgical field directly after suction is removed, 5 - severe bleeding, constant suctioning required; bleeding appears faster than can be removed by suction; surgical field severely threatened and surgery usually not possible). recently, pupillary dilatation reflex (prd) was added as a surrogate variable showing the nociception-antinociception balance into above mentioned parameters constituting a novel approach in monitoring patients intraoperatively, known as adequacy of anaesthesia (aoa) or tailor-made anaesthesia. prd value \>5% reflects increased sensitivity to painful stimulus it constitutes the indication for administration of rescue analgesia intraoperatively. this study aims at evaluating utility of prd-directed analgesia using remifentanil on the intraoperative blood loss, haemodynamic stability and time duration of surgery in patients undergoing functional sinus surgery (fess) under total intravenous anaesthesia using propofol or volatile anaesthesia using sevoflurane or desflurane currently, fess is most often performed using total intravenous anaesthesia (tiva) which is by majority of anaesthesiologists believed to reduce the intraoperative blood loss compared to general anaesthesia using volatile anaesthetics, but current literature provides conflicting findings in this area if the sort of anaesthetic used influences quality of the surgical field.

Eligibility criteria:
inclusion criteria: * - written consent to participate in the study * written consent to undergo functional endoscopic sinus surgery under general anaesthesia * asa (american society of anesthesiologists) i-iii exclusion criteria: * age under 18 years old * allergy to propofol * pregnancy * any anatomical malformation making prd or se measurement impossible

Keywords: pupillary dilatation reflex (prd) intraoperative blood loss (ibl) boezaart bleeding scale (bbs) spectral entropy (se) adequacy of anaesthesia (aoa) total intravenous anaesthesia (tiva) sevoflurane desflurane